1. Field of the Invention
The present invention relates to a wiring body used for manufacturing a substrate. Also, the present invention relates to such a substrate and a manufacturing method thereof.
2. Description of the Related Art
The present inventors previously invented a method for manufacturing a substrate, having penetrating via conductors, comprising the steps of: arranging a large number of fine metallic wires made of metal such as copper, in a container so that they can be parallel with an axis of the container; charging the container with dispersed solution in which ceramic powder, such as alumina, to be fired at high temperature is dispersed; drying solution in which ceramic powder is dispersed; firing the dried body of ceramic powder at a high temperature at which ceramic powder can be sufficiently densely sintered so as to obtain a dense columnar sintered body, wherein the temperature is not lower than a melting point of the metallic fine wires; and slicing the columnar body perpendicularly to the axis thereof.
According to the above-mentioned method, the metallic fine wires are liquidized in the process of sintering of ceramic powder to be fired at high temperature. Accordingly, even in the case of contraction of a ceramic when it is fired, the metallic fined wires are not cut off, and it is possible to manufacture a substrate having via conductors, the pattern of which is highly dense. It was confirmed by the inventors that the liquidized metallic fine wires are not dispersed in the ceramic.
The present inventors further invented a method for manufacturing a substrate having penetrating via conductors comprising the steps of: arranging a large number of fine metallic wires in a container so that they can be parallel with an axis of the container; charging the container with ceramic powder to be fired at a low temperature, the principal component of which is glass; firing the ceramic powder at a low temperature not higher than a melting point of the metallic fine wires so as to obtain a dense columnar sintered body; and slicing the columnar body perpendicularly to the axis.
According to the above method, ceramic powder to be fired at a low temperature, the principal component of which is glass, is melted in the process of firing. Therefore, no stress is given to the metallic fine wires. Consequently, it is possible to obtain a substrate having via conductors, the metallic wires of which are not cut off.
However, when the former method is employed, the following problems may be encountered. According to the former method, ceramics to be fired at high temperature contract at a high coefficient of contraction of about 40%. Therefore, the dimensional accuracy is lowered. Since ceramic powder is fired to be densified, the hardness of the fired body is very high, so that it is impossible to slice the fired body easily. When an additive is added to a ceramic powder so as to lower the hardness, the mechanical strength is disadvantageously lowered.
When the latter method is employed, the following problems may be encountered. The latter method uses ceramics to be fired at low temperature, the principal component of which is glass. Therefore, the fired body is fragile, and the mechanical strength is not sufficiently high.